OpenSCAD configurable Hirth joints

This is a remix which adds a customizable Hirth joint in triangle, rectangular, and square tooth forms.

It does not work within the Thingiverse customizer because of dependencies on librearies unavailable in Thingiverse:

* https://github.com/openscad/scad-utils
* https://github.com/openscad/list-comprehension-demos
* https://github.com/GillesBouissac/agentscad

It does work in OpenSCAD.


There are several half-Hirth joints .stls of various numbers of teeth, which could be used as indexers or index plates

* 5 Teeth - pentagons and 72° indexing, 5 position index plate
* 12 teeth - 30° degree indexing, 2, 3, 4, 6, 12 positition index plate
* 36 Teeth - 10° indexing, 2, 3, 4, 6, 9,12, 18, 36 position index plate
* 60 Teeth - 6° indexing, 2, 3, 4, 5, 6, 9,12,18, 60 position index plate

With the OpenSCAD customizer, you can choose the number of teeth


See also: https://www.thingiverse.com/thing:5574308 which implements a "cone angle" between the axis and the plane